Avert Steam Pipeline And Piping Failure And Steam Leaks In The Field

摘要

Steam piping and pipeline whipping, bowing, buckling and jumping are some of the phenomenon observed in the field due to improper design and inadequate commissioning procedures. As a result, ‘steam flood’, ‘cyclic steam stimulation’ and ‘SAGD’ operations experiences long steaming hold‐ups, extended shutdowns, production losses and environmental clean‐up Steam pipelines up to 32” diameter and 30 km length, with 11 ‐ 15 MPa design pressure and 250‐340 deg C design temperature for quality of steam from 80 to 100%, are being designed with high strength material and thin wall designs. Although, designs are robust and utilizes proven stress analysis tools, but are often fail to address the common field issues of unequal warming, condensate buildup and severe slugging encountered during the commissioning and at the start of the new steaming cycle. Also, piping connections lack the provision to accommodate requisite thermal growth and/or the unequal thermal growth between steam piping, production piping, well heads, batteries headers, leading to severe steam leaks. Steam pipeline and piping are designed with anchors and guides to deal with thermal growth in the horizontal plane. When steam is charged at the ambient temperature, the cooling of the steam in long length pipelines and resulting condensate build up cause thermal gradient in the pipe wall. This thermal gradient coupled with transition in the piping and pipeline elevations are mainly responsible for the bowing, jumping and whipping phenomenon. Pressure, temperature and strain gauge instrumentation should be installed at strategic location to closely monitor and execute uniform warming up to avoid whipping, bowing, buckling and jumping of steam piping and pipelines. Every incident of whipping, bowing, buckling and jumping of steam piping & pipelines requires detailed integrity evaluation of the affected sections, prior to putting back into operation. Detailed assessment of wall thinning, ovality, dents and other mechanical damages are mandatory to comply with thin wall designs. The result in most incidents is complete replacement of the affected sections, requiring prolonged and costly shutdowns and risk to the producing reservoir due to lack of pressure.